RC 187 
.08 

Copy 1 



021 623 



Typhoid Fever and 
Its Sequelae 



Read before the Section on Vital Statistics, 
American Public Health Association, 
Jacksonville, Fla., December, 1914 



BY 

LOUIS I. DUBLIN, Ph.D., Statistician 
Metropolitan Life Insurance Company, New York 
1914 



^ transfei 

JUL 2 ,9,5 



TYPHOID FEVER AND ITS SEQUEL.E. 



Our problem in this study was to measure the effect of typhoid fever 
upon vitahty during the first three years following recovery, and also to 
note the causes of death which predominate during this period. 

Records Used. 

For this purpose, we turned to the reports of the Visiting Nurse Service 
of the Metropolitan Life Insurance Company for the year 1911. In that 
year, 1,936 cases of typhoid fever were recorded. A fairly complete record 
of the illness in these cases was available. A further advantage in this 
series was the fact that the subsequent whereabouts and condition of those ' 
who were treated could be obtained from the insurance records. In this 
way, we could at once be informed with regard to the present status of these 
persons; whether they were living or dead, the date of death, as well as a 
complete record of the conditions at death in these later cases. It was, in 
other words, possible for us to trace this series fairly completely and to 
determine the consequences and effects of typhoid fever on these persons. 

An examination of our 1,936 cases led to the elimination of 362 in which 
the record did not appear satisfactory from ih^ point of view of accu- 
racy of diagnosis. As a result, we had, after careful analysis, a residue 
of 1,574 cases. All of these presentedrs^jsfaetory evidence, so far as such 
records alone could, that the patient had suffered from an attack of "ty- 
phoid fever" at the time of 1911 nursing. The cases were in the hands of 
physicians and nurses. The treatment of the disease in every case indi- 
cated typhoid fever. The duration of the service as well as the large num- 
ber of visits made, all pointed conclusively that our series was well selected 
and sound. The average number of visits made per case by our Visiting 
Nurse Service to these patients was close to seventeen (16.85) and the dura- 
tion of nursing was close to twenty-four (23.87) days. 

Distribution by Age and Sex. 

Table 1 shows the distribution of the 1,574 cases by age and sex. It 
will be noted at once that 70.3 per cent, of the total cases were under twenty 
years of age and that 34.1 per cent, were under ten years. This proportion 
is somewhat higher than that usually observed in other typhoid fever series. 
The explanation lies in the fact that our Visiting Nurse Service is more 
readily availed of by women and children. It is important also to remem- 
ber this large incidence at the earlier ages in view of its bearing on Our find- 
ings later with reference to the sequelae. 



TABLE 1. 

DISTRIBUTION BY AGE AND SEX OF 1,574 CASES OF TYPHOID FEVER. 
Visiting Nurse Service, 1911, Metropolitan Life Insurance Company. 





Males and females. 






Age period. 






Males. 


Females. 




Number. 


Per cent. 






TTTirJia»» 1ft 


536 


34.1 




/loo 


10-19 


570 


36.2 


254 


316 


20-29 


230 


14.6 


85 


145 


30-39 


114 


7.2 


35 


79 


40-49 


81 


5.2 


23 


58 


50 and over 


43 


2.7 


17 


26 


Total — -all ages 


1,574 


100.0 


665 


909 






Per cent, of total — by sex 




100.0 


42.3 


57.7 



Lethal Rates. 

Table 2 presents the lethal rate per 100 treated for each period. The 
least rate is that for the children under ten; the highest trustworthy rate 
is for the group 20-29 which was 13.91 per 100. At the higher ages there 
are too few exposed to make the rate dependable. For the entire series 
of 1,574 cases treated, the lethal rate was 9.28 per 100 treated. This figure 
is consistent with that of other series which vary slightly above and below 
a mean of 10 deaths per 100 cases treated. 

TABLE 2. 

LETHAL RATES PER 100 CASES TREATED FOR TYPHOID FEVER- 
CLASSIFIED BY AGE PERIOD. 
Visiting Nurse Service, 1911, Metropolitan Life Insurance Company. 







Number died 


Lethal rate 


Age period. 


Number treated. 


under treatment. 


per 100 treated. 


Under 10 


536 


36 


6.72 


10-19 


570 


45 


7.89 


20-29 


230 


32 


13.91 


30-39 


114 


12 


10.53 




81 


13 


16.05 


50 and over 


43 


8 


18.60 




1,574 


146 


9.28 



2 



Complications. 



Table 3 shows the complications in these 146 cases. These are important 
in view of our interest in the sequelse to be referred to later. Interest 
should be centered in the fact that over 15 per cent, involve intestinal per- 
foration, hemorrhage, peritonitis and other similar conditions. Meningitis 
and pneumonia were present in 10.3 per cent, of the fatal cases, heart con- 
ditions in 8.2 per cent, of the cases. Other complications, such as tuber- 
culosis and acute nephritis indicated that the lungs and kidneys were im- 
paired in a considerable number of cases in connection with the typhoid 
infection. 

TABLE 3. 

COMPLICATIONS IN 146 FATAL CASES OF TYPHOID FEVER. 

Visiting Nurse Service, 1911, Metropolitan Life Insurance Company. 



Complications with typhoid fever. 


Number of 
deaths. 


Per cent, of 
total deaths. 




60 


41.1 




22 


15.1 




15 


10.3 




15 


10.3 




12 


8.2 


Tuberculosis (all forms) 


8 


5.5 


Acute nephritis 


4 


2.7 




10 


6.8 




146 


100.0 



Distribution of Recovered Cases. 

Table 4 shows the distribution by age and sex of the 1,428 persons who 
recovered from the typhoid fever. This distribution is very slightly dif- 
ferent from that of Table 1 which showed the distribution of the initial 
cases. 

Relation Actual to Expected Mortality. 

From this point onward, our effort was directed to a comparison of the 
actual and expected mortality among the 1,428 surviv^ors. Our method 
was as follows: The 1,428 cases were distributed by sex and color and by 
ten-year age periods. A separate schedule was prepared for each sex and 
color. The mortality rates of the Company for each individual age. sex 
and color class was employed as a standard. We assumed that the mor- 

3 



TABLE 4. 

DISTRIBUTION BY AGE AND SEX OF 1,428 PERSONS WHO RECOVERED FROM 

TYPHOID FEVER. 

Visiting Nurse Service, 1911, Metropolitan Life Insurance Company. 





Males and females. 






Age period. 






Males. 


Females. 




Number. 


Per cent. 






Under 10 


500 


35.0 


239 


261 


10-19 


525 


36.8 


232 


293 


20-29 ; 


198 


13.9 


68 


130 


30-39 


102 


7.1 


30 


72 


40-49 


68 


4.8 


14 


54 


50 and over 


35 


2.5 


9 


26 


Total — all ages 


1,428 


100.0 


592 


836 






100.0 


41.5 


58.5 



tality actually experienced in 1911 by the Company in the Industrial De- 
partment should serve as the measure of the expected deaths for the cor- 
responding group of these persons who had recovered from typhoid fever 
in 191 1 for the first year after recovery. For the second year after recovery, 
we employed similar mortality figures for the year 1912 as a standard and 
for the third year we emplo^^ed the figures for 1913. In other words, the 
mortality table used was not an arbitrary measure but exhibited the death- 
rates which persons of the jsame sex, color and age among our Industrial 
policyholders actually experienced. By throwing these rates into the num- 
ber of years of life of each group in successive years since recovery we 
obtained the number of expected deaths for each age period. 

In this way we found, as shown in Table 5, that in the series of 1,428 
persons the expected number of deaths was equal to 26.45. As a matter 
of fact, our record showed 54 actual deaths. The ratio of actual to ex- 
pected deaths was, therefore, for our entire series, 204 per cent. In other 
words, more than twice the mortalitj^ expected was realized. You will 
note that the total number of years of life was nearly 8,850 years. 

A number of persons dropped out, either by death or lapsing their policies 
during the first, second or third year after recovery. Each such exit from 
our series involved an adjustment in the number of years of life exposed to 
risk, by taking the proportionate part of a year from the date of recovery 
to the date of exit. In this way, every day of experience was used. For- 
tunately, the fullness of the Company's record made this much desired 



TABLE 5. 

COMPARISON OF ACTUAL AND EXPECTED MORTALITY IN THREE YEARS 
FOLLOWING RECOVERY FROM TYPHOID FEVER— CLASSIFIED BY AGE 
PERIOD. 

Cases Treated by Visiting Nurse Service, 1911, Metropolitan Life Insurance 

Company. 



Age period. 


Number of 
years of life. 


Number of 
expected deaths. 


Number of 
actual deaths. 


Per cent, 
actual of 
expected deaths. 


Under 10 


1,354.15 


8.07 


13 


161 


10-19 


1,434.66 


5.61 


12 


214 


20-29 


521.27 


3.92 


13 


332 


30-39 


274.16 


2.94 


5 


170 


40-49 


173.05 


2.46 


8 


325 


50 and over 


92.62 


3.45 


3 


87 


Total — ^all ages. . . . 


3,849.91 


26.45 


54 


204 



step possible. It would be difficult in many other services to keep such 
complete control of the whereabouts of the individuals composing a large 
series. Our conclusion from our own series is, therefore, that during the 
first three years after recovery from typhoid fever, the mortality is twice 
the normal. 

It is interesting to note, however, that this increased rate is not uni- 
formly evident in all the three years of the series. Thus, in the first year 
following recovery from typhoid fever the ratio of actual to expected 
deaths was 284, in other words nearly three times as great as it should be. 
In the second year, the percentage actual of expected deaths was 217, and 
in the third year it fell below the expected, namely to 80 actual deaths per 
100 expected deaths. This last fact is puzzling. A careful reexamination 
was made of our series. No effort was spared in finding a possible source 
of error and yet at the very end, we find no evidence of an additional death 
which would in any way change our figure. 

It would appear from our figures that typhoid fever has its impairing 
effect in the first two years after recovery. It would seem, although we 
would not press this explanation, that the weaklings had been eliminated by 
the immediate deaths and those that followed in the first two years after 
recovery. Table 7 shows the causes of death in the 54 cases that occurred 
in the three years subsequent to recovery. Tuberculosis heads the list with 
twenty-one deaths (39 per cent.), of which all but three cases were of 
the pulmonary type. The second important group are the diseases of the 
heart with a total of eight cases. Pneumonia, and kidney disease follow 
with four cases each. 

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Our conclusion, then, from this table is that the incidences of tuberculosis 
and the diseases of the heart are increased subsequent to typhoid fever. 
This is borne out by the previous statement of complications which oc- 
curred in the immediate deaths, Table 3, where a considerable number of 
cases showed heart and pulmonary complications. This condition has 
been noted consistently by other observers of typhoid fever and its sequelae. 

Effect of Sequels upon General Death Rate. 

We will close this paper with an estimate of the effect of typhoid fever 
upon mortality in the three years subsequent to an attack. On the basis of 
the estimated population of Continental United States in 1914, we have 
calculated that each year a minimum of close to 8,000 deaths occur which 
can be attributed annually to the impairments which follow typhoid fever. 
In this estimate, we have assumed a minimal death-rate from typhoid fever 
of 20 per 100,000. We have also assumed the number of cases to be ten 
times as great as the number of deaths in accordance with the usual practice. 
The number of recoveries, therefore, is 90 per cent, of the cases. For each 
of the three years following, we have assumed an expected death-rate for 
the entire country to be at least 15 per 1,000 from all causes. A calcula- 
tion of the additional deaths due to sequelae of typhoid fever gives us a 

TABLE 7. 

CAUSES OF 54 DEATHS IN THREE YEARS FOLLOWING RECOVERY AMONG 
1.428 CASES OF TYPHOID FEVER. 

Treated By Visiting Nurse Service, 1911, Metropolitan Life Insurance Company. 



Cause of death. 



Number of deaths. Per cent, of total deaths. 



Tuberculosis : 

Pulmonary 

Other forms 

Diseases of the heart: 

Endocarditis 

Myocarditis 

Valvular disease of the heart 

Pneumonia 

Nephritis: 

Acute 

Bright's disease 

Acute articular rheumatism . , . 

Violent causes 

Other causes 

Total — ajl causes 




5.6 

7.4 
3.7 
3.7 
7.4 

1.9 
5.6 
3.7 
13.0 
14.8 



54 



100.0 



7 



total of 7,781. This is the price that is paid annually over and above the 
registered direct loss from typhoid fever according to the results of our 
study. It is not only the 20,000 immediate deaths that we have to con- 
sider, but the additional 8,000 who, although recovered, cannot survive 
the strain which modern industrial life makes necessary and who either 
because of tubercular or cardiac lesions die untimely deaths within the 
first or the second year after recovery. 

TABLE 8. 

ESTIMATED NUMBER OF DEATHS TO BE ATTRIBUTED ANNUALLY TO 
SEQUELiE OF TYPHOID FEVER IN THE UNITED STATES. 



Population, Continental United States, 1914 98,781,32-t 

Typhoid Fever: 

Death rate per 100,000, Continental United States, 1914 (minimal estimate) ... 20 

Deaths in United States in 1914 19,800 

Cases in United States in 1914 198,000 

Recoveries, each year, in United States 178,200 

Extra deaths to be attributed annually to sequelae of typhoid fever. (On basis 

of double mortality in three years following recovery) 7,781 



n 



, IBRftRV OF CONGRESS 



